In an internal combustion engine provided with a crank angle sensor for detecting a rotation state of a crankshaft, there is known control for detecting generation of a combustion change and stabilizing the combustion change.
However, in a case where the combustion change of the internal combustion engine is detected and suppressed, a detection means for information showing an indicator of the combustion change and a suppression means are not clear.
Meanwhile, there is a known control apparatus of an internal combustion engine including a combustion parameter control means for controlling a combustion parameter acting on combustion of the internal combustion engine, and including a combustion state detection means for, when the combustion parameter acting on the combustion of the internal combustion engine is altered by the combustion parameter control means, sampling information for detecting a combustion state based on the altered combustion parameter at a predetermined timing (for example, see PTL 1).
According to PTL 1, it is determined whether or not it is an ignition time. When the ignition time is determined, it is determined whether or not a 30° CA signal is detected after the ignition time is determined. When the 30° CA signal is not detected, it is not a detection time of a rotational velocity Ne. In a case where the 30° CA signal is detected, a processing of calculating the rotational velocity in accordance with the ignition time is performed. In such a way, PTL 1 describes that since the rotational velocity is detected in accordance with the ignition time, the combustion state can be detected even upon altering the ignition time.